Origin - Native to U.S.
Other info. - In the "Flora of Missouri" Steyermark mentioned that this species should be cultivated more. Well someone listened because the plant is popular in cultivation now. A synonym for the plant is H. prolificum and the name is fitting because the plant produces a multitude of bright yellow flowers when in full bloom.
Flowers - Petals 5, yellow, distinct, to +/-1.5cm long, 7mm broad, glabrous, oblong to narrowly obovate, rounded at apex. Stamens many, (+100), erect. Filaments yellow, 8-9mm long, glabrous. Anthers yellow, .6mm broad. Style 4-5mm long, glabrous. Ovary superior, ovoid, glabrous, pale greenish-yellow, 4mm long, 2mm in diameter, 3-locular. Placentation axile, ovules(seeds) many. Sepals 5, unequal, to 6mm long, +/-3mm broad, glabrous, acute, spreading to slightly recurved.
Flowering - June - September.
Habitat - Rocky open ground, streambanks, bluffs, wooded slopes, low moist ground, also cultivated.